Publications by authors named "Mário Moreira"

29 Publications

  • Page 1 of 1

Properties of zinc titanates synthesized by microwave assisted hydrothermal method.

Heliyon 2021 Mar 16;7(3):e06521. Epub 2021 Mar 16.

Universidade Federal de Pelotas, Pelotas RS, Brazil.

Zinc titanates are compounds that have shown great application versatility, including in the field of semiconductors. Solid state reactions, the polymeric precursor method and the hydrothermal method are the most mentioned synthesis of these compounds in the literature. In the present work, we use microwave assisted hydrothermal method (MAH) to synthesize zinc titanate and evaluate its potential for solar cell applications through structural and optical characterization techniques. The synthesized samples were also subjected to a variable temperature heat treatment in the range of 500 °C-800 °C. The analysis showed that the crystallization of the material starts at 500 °C and that samples submitted to temperatures of 600 °C-800 °C showed the formation of two phases of zinc titanates, being a cubic phase of ZnTiO, considered rare in the literature, predominant up to a temperature of 800 °C. The optical characterization, based on the techniques of photoluminescence spectroscopy and UV-Visible spectroscopy, showed that the photoluminescent activity and the energy of the band gap increased with the increase of the temperature of the heat treatment, having the highest response in 700 °C, facts that can be linked to the predominant formation of the cubic phase of ZnTiO and simultaneous of the cubic and rhombohedral phases of ZnTiO at 700 and 800 °C. Finally, we highlight as the most important results, the fact that it was possible to obtain these titanates at a temperature lower than that reported in the literature, and that the heat-treated sample at 500 °C is the one with the lowest energy expenditure to be synthesized and the one with the greatest potential for application in dye-sensitized solar cells (DSSC's).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.heliyon.2021.e06521DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7988328PMC
March 2021

Change in Domains that Influence Quality of Life after Major Lower Limb Amputation in Patients with Peripheral Arterial Disease.

Ann Vasc Surg 2021 Feb 5. Epub 2021 Feb 5.

Angiology and Vascular Surgery Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Background: Recent guidelines raise the concept of the importance of health-related quality of life (QoL). Change in QoL after amputation in ischemic patients is not well described. We aim to evaluate the change in quality of life after major limb amputation in patients with peripheral arterial disease.

Methods: We retrospectively identified all patients submitted to above-knee amputation (AKA) and below-knee amputation in our vascular surgery department in a 2-year period. Trauma excluded. A vascular amputee adapted QoL questionnaire was administered comparing the last 2 weeks to the 2 weeks before amputation. It included subjective and objective questions adapted from WHOQoL-BREEF and SF-36 divided into specific domains of QoL (physical health, role physical, pain, social, and psychological health) that were compared to 2 global items (overall QoL and general health). Independent samples tests and linear correlations were calculated.

Results: A total of 106 patients were included, 30-day mortality rate 16.3% and 1-year 39.1%. Patients had an increase in mean total score after amputation of 14.35 out of 100 points, with an improvement of 52.1 points in pain and 11 points in social and psychological health out of 100 (P<0.001). Physical health and role physical scores decreased after amputation. Overall QoL was correlated with total score (P<0.001). Mean QoL total score after amputation was 79.0% ± 12.6. In general, amputees scored higher in the domains social and psychological health. Older people, women, AKA and bilateral amputees had lower physical health scores (P<0.05), prosthesis was correlated with improvement in physical health after amputation (P = 0.026). Elderly and married people had big improvement in overall QoL after amputation (P = 0.008 and P = 0.056, respectively).

Conclusions: QoL does not seem to diminish in advanced ischemic patients after amputation. Older people value more a decrease in pain and family support over physical health. Therefore, patient oriented treatments should be preferred. Future research should be made to validate a disease-specific questionnaire for this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.avsg.2021.01.082DOI Listing
February 2021

Impact of Total Psoas Area and Lean Muscular Area on Mortality after Endovascular Aortic Aneurysm Repair.

Ann Vasc Surg 2021 Apr 16;72:479-487. Epub 2020 Sep 16.

Angiology and Vascular Surgery Department, Centro Hospitalar e Universitário de Coimbra, EPE, Praceta Professor Mota Pinto, Coimbra, Portugal.

Background: Sarcopenia has assumed growing relevance as a morbimortality predictor after major abdominal surgery. The aim of this study is to access total psoas muscle area (TPA) and lean muscle area (LMA) impact in morbimortality after elective endovascular abdominal aortic aneurysm repair (EVAR).

Methods: Asymptomatic patients submitted to aortic endoprosthesis implantation between January 1, 2014 and December 31, 2018 at our vascular surgery department were retrospectively evaluated. After exclusion criteria were applied, 105 patients were included in the study; preoperative computed tomography scans were evaluated using OSIRIX software (Bernex, Switzerland). Two observers independently calculated TPA at the most caudal level of the L3 vertebra and respective density, therefore calculating LMA. Patients were separated by tertiles with the lowest being considered sarcopenic and with higher muscle steatosis and compared with the higher tertiles. Patient demographics and intraoperative and postoperative period variables were collected. Charlson comorbidity index was calculated and surgical complications classified according to Clavien-Dindo. The intraclass correlation coefficient and Bland-Altman plot were made to characterize interobserver variability. Survival analysis was performed with the Kaplan-Meier method, and differences between survival curves were tested with the log-rank test. The effect of sarcopenia on patient survival was assessed using Cox proportional hazard models.

Results: Considering TPA, univariate analyses revealed that patients in the lower tertile had inferior survival (P = 0.03), whereas multivariate analyses showed increased likelihood of mortality (P = 0.039, hazard ratio (HR) 3.829). For LMA, univariate analyses revealed that patients in the lower tertile had inferior survival (P = 0.013), whereas multivariate analyses showed increased likelihood of mortality (P = 0.026, HR 4.153). When analyzing patients in the lowest tertile of both TPA and LMA, both univariate (P = 0.002) and multivariate (P = 0.018, HR 4.166) analyses reveled inferior survival.

Conclusions: Our study reveals reduced survival in patients with low TPA and low LMA submitted to elective EVAR; these factors should probably be taken into consideration in the future for preoperative risk evaluation and surgical planning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.avsg.2020.09.004DOI Listing
April 2021

Is There an Impact of COVID-19 on Admission of Patients to the Emergency Department for Vascular Surgery?

Ann Vasc Surg 2020 Nov 11;69:100-104. Epub 2020 Aug 11.

Cirurgia Vascular, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Background: On March 2020, the World Health Organization declared the coronavirus disease 2019 outbreak a pandemic. During this period, surgical activity and admission to the Emergency Department (ED) decreased globally. The aim of this article is to understand how the admission of a patient to the ED for vascular surgery changed in our center in Portugal and if this situation prevented urgent surgical procedures.

Methods: Through a retrospective study, we compared the volume of patients admitted to the ED during the emergency state (ES) in Portugal with the same period in 2019. In addition, we analyzed the urgent surgical activity during the ES and in the correspondent period of the previous 10 years, regarding limb acute ischemia, acute aortic pathology, and vascular trauma. Two groups of patients were formed-patients operated during the ES and during the non-ES, for control. Statistical analysis was performed using IBM SPSS® Statistics, version 25.

Results: In the ES, 115 patients were observed at the ED and 179 in the 2019 corresponding period. During the ES, patients significantly recurred less to the ED directly from home (P < 0.001) and were less referred to the ED by primary care doctors (P < 0.001). Patients observed at the ED were significantly more urgent-required urgent surgery or were admitted to the department-than those in 2019 (40% vs. 24%). However, there were no differences when only considering urgent surgery (14% in ES vs. 10% in 2019). In the ES, 38% of patients observed at the ED were discharged with no follow-up related to vascular surgery against 60% in 2019, although this difference was not significant. Compared with the preceding 10 years, there are not significant differences in the number of patients who underwent urgent surgery in both ES and non-ES periods. In patients with acute limb ischemia, we did not find an increase in the time between onset of symptoms and ED admission, during the ES.

Conclusions: Fewer patients were admitted at the ED during the ES, and those admitted were significantly more urgent. We did not find a decrease in the number of urgent surgeries when compared with the preceding 10 years. Therefore, we cannot assume that coronavirus pandemic precluded urgent surgical procedures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.avsg.2020.08.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417287PMC
November 2020

Aortic Anastomotic Aneurysm After Infra Renal Grafting.

Rev Port Cir Cardiotorac Vasc 2020 Apr-Jun;27(2):145

Angiology and Vascular Surgery Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

An 87 year-old male presented with a 71mm proximal anastomotic aneurysm causing left renal artery displacement (Figures 1 and 2), 19 years after infra-renal aorto-aortic grafting for an infra-renal abdominal aortic aneurysm. Dilatation of visceral aorta was also observed. Management would be challenging but patient denied further intervention.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2020

Influence of Eu valence on the optical activity of BaTiO decorated with CaF synthesized by microwave-assisted hydrothermal method.

Dalton Trans 2020 Jul 11;49(25):8540-8548. Epub 2020 Jun 11.

Physics Post Graduate Program, Federal University of Sergipe, São Cristóvão, SE, Brazil.

Inorganic hybrid materials have promising applications in absorbers and for the photon harvesting of solar irradiation, such as in DSSC photoanodes. Moreover, investigation of the interactions between the photoanode constituent materials is extremely important, since it is known that the properties of the materials are strongly dependent on the nucleation and growth process. Therefore, the purpose of this work was to synthesize a system consisting of a synergic combination of two inorganic hosts, BaTiO and CaF, synthesized together through a microwave-assisted hydrothermal method, which allows single-phase materials to be obtained after short synthesis times and at low temperatures. The increase in optical activity was investigated after the insertion of Eu ions. From the structural results, it was possible to observe that the method used to obtain the system was efficient, even using temperatures as low as 140 °C and a reaction time of one minute. The optical properties (emission and excitation) were evaluated in the visible and VUV region from 2.5 to 10.5 eV. The XANES Eu L edge differences associated with the XEOL results indicate that the synthesis method incorporated Eu in the hosts and the surface of the two compounds, BaTiO and CaF. Therefore, the combination between the Eu activators and the F centers of the host increased the range for photon harvesting, making these systems a promising material for future applications in photoanodes for DSSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0dt01321hDOI Listing
July 2020

Inferior Thyroid Artery Pseudoaneurysm Coil Embolisation.

Eur J Vasc Endovasc Surg 2020 Jun 1;59(6):917. Epub 2020 May 1.

Medical Imaging Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejvs.2020.03.046DOI Listing
June 2020

Structural and Electronic Properties of Bulk ZnX (X = O, S, Se, Te), ZnF, and ZnO/ZnF: A DFT Investigation within PBE, PBE + , and Hybrid HSE Functionals.

J Phys Chem A 2020 May 4;124(19):3778-3785. Epub 2020 May 4.

Department of Physics, Federal University of Pelotas, P.O. Box 354, 96010 900 Pelotas, RS, Brazil.

Here, we have studied the crystalline structure of bulk ZnX (X = O, S, Se, Te) and ZnF systems as a first step to understand the structures like ZnX and Zn-based systems like ZnO/ZnF interfaces, which are of utmost importance for possible technological applications. In addition, an adequate methodological description based on density functional theory (DFT) calculations is necessary. It is well known that plain DFT calculations based on local or semilocal exchange-correlation functionals fail to describe the correct band gap energy for these systems, whereas nonlocal approaches, such as hybrid-based functionals, can compensate the underestimation of band gap. To contribute to the assessment, DFT studies were performed within semilocal Perdew-Burke-Ernzerhof (PBE) and two nonlocal functionals, hybrid Heyd-Scuseria-Ernzerhof (HSE) and PBE + functionals. Our results confirm that PBE underestimates the energy band gap values, from 33.0 to 42.8% for ZnX compounds compared to the experimental values. Applying the hybrid HSE functional, we obtained a band gap dependency in relation to the range of separation of the nonlocal exact exchange, in general decreasing the band gap error and improving the lattice constant description. In addition, using the PBE + approach, we have investigated the localization of the Zn d-states and its effect on the band gap in ZnX and ZnF. We found an increase in the band gap with increasing Hubbard parameter, which introduces on-site Coulomb corrections for the Zn 3d states. In the same context, the relevance to include the Hubbard corrections for the O 2p states (and X p states) is highlighted. Thus, considering PBE + , the error in ZnO band gap, for example, decreases to 5.1%, in relation to the experimental value. Finally, ZnO-12L/ZnF-4L superlattices are found to exhibit conventional electronic properties, such as low fundamental band gap, smaller than either of the parent materials. Our first-principles calculations reveal that the unexpected band gap reduction is induced by the conducting layers that tend to penetrate the interface and decrease the band gap, leading to the transport of carriers through the interface to ZnF, which, even with a high band gap for charge transfer, can be interesting for photovoltaic applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpca.9b11415DOI Listing
May 2020

Combined Endovascular Exclusion with Percutaneous Sac Aspiration and Thrombin Injection in the Management of Popliteal Artery Aneurysm.

Ann Vasc Surg 2020 Jul 1;66:662-664. Epub 2020 Feb 1.

Angiology and Vascular Surgery Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Background: Symptomatic popliteal artery aneurysms (PAAs) can be managed by open surgery or endovascular exclusion.

Methods: The authors describe a case of a 68-mm PAA causing compressive symptoms and managed by endovascular exclusion combined with percutaneous sac decompression.

Results: Endovascular exclusion allows sac pressure reduction. Additional percutaneous sac aspiration and thrombin injection promote sac shrinking and avoid persistent collateral flow.

Conclusions: In challenging cases, matching different techniques can be helpful.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.avsg.2020.01.084DOI Listing
July 2020

[The Impact of Patient Transfer After Rupture of an Abdominal Aortic Aneurysm].

Rev Port Cir Cardiotorac Vasc 2019 Oct-Dec;26(4):273-277

Serviço de Angiologia e Cirurgia Vascular, Centro Hospitalar e Universitário de Coimbra, Portugal.

Objective: determine whether patient transfer adversely affects the survival of ruptured abdominal aortic aneurysm (rAAA) patients after conventional surgery.

Methods: We performed a retrospective review of all patients undergoing attempted repair of an rAAA at a tertiary center, over January 2008 and December 2014. Patients were divided into those presenting directly to our center and those transferred from another hospital. The main outcome variable was 24-hour or 30-day mortality, with secondary variables including time to surgical treatment, length of intensive care unit stay and total length hospitalization.

Results: 78 patients (88% men) underwent attempted open repair of an rAAA during this period, 69% (54 cases) were transferred from another institution. Both groups were similar in terms of demographic characteristics, comorbidities and hemodynamic stability. The overall mortality rate was 51% at 30 days. Transferred patients took twice as long as direct patients to get to the operating room (median 7,9 vs. 3,9 horas, p < 0,05), Although the difference for surgery treatment, there was no difference in 24-hour and 30-day mortality between the transferred group and direct group (26% e 50% vs. 29% e 58%, p < 0,05). Mean intensive care unit stay (median, 12 vs. 4 dias, p = 0,04) and total hospitalization (median 11 vs. 4 dias, p = 0,04) were sustantially superior in the transferred group.

Conclusions: Transfer of patients with RAAA in this series results in a doubling of the time interval between initial patient presentation and arrival in the operating room. This, however, did not result in any disadvantage in the survival rate between the groups. The total length and resources consumption were higher in the transfer group. These results may be attributed to a pre-selection of patients (clinically stable) who are able to tolerate such a delay in surgical treatment, secondary to transfer.
View Article and Find Full Text PDF

Download full-text PDF

Source
March 2020

External Iliac Artery Laceration Caused by Hip Prosthesis Migration.

Rev Bras Ortop (Sao Paulo) 2019 Sep 27;54(5):597-600. Epub 2019 Aug 27.

Serviço de Angiologia e Cirurgia Vascular, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Hip arthroplasty is a common and safe intervention in orthopedic surgery. However, the proximity of this joint to large vessels makes the occurrence of vascular injury a rare but serious and possibly lethal complication of this surgical technique. Acute vascular injuries in the context of a hip arthroplasty have variable etiologies and clinical presentations, and are more common in revision surgeries and in situations of medial intrapelvic migration and of chronic infection of the hip prosthesis. In the present article, the authors present a case of acute and late major vascular complication in the context of hip arthroplasty revision. The patient developed an acute laceration of the external iliac artery caused by chronic and progressive medial intrapelvic acetabular migration of the hip prosthesis associated with chronic infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rbo.2017.09.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6819160PMC
September 2019

Quantitative evaluation of the surface stability and morphological changes of CuO particles.

Heliyon 2019 Oct 1;5(10):e02500. Epub 2019 Oct 1.

Modeling and Molecular Simulations Group, São Paulo State University, UNESP, 17033-360, Bauru, SP, Brazil.

CuO low-index surfaces periodic models have been simulated based on density functional theory. The calculated surfaces energies allowed estimating the morphology by means of the Wulff theorem as well as the investigation of possible paths of morphological changes. Therefore, systematic morphology diagrams and change paths according to the energy modulation in relation to the surfaces stabilizations were elaborated. The applicability of this strategy was exemplified by comparing the obtained results with experimental available data from the literature. The morphology diagrams with the quantitative energetic point of view can be used as a guide to support experimental works in order to understand the relation between surface interactions and crystal growth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.heliyon.2019.e02500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812201PMC
October 2019

Unveiling the efficiency of microwave-assisted hydrothermal treatment for the preparation of SrTiO mesocrystals.

Phys Chem Chem Phys 2019 Oct;21(39):22031-22038

Laboratory of Nanostructured Multifunctional Materials, Federal University of São Carlos, Rodovia Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil.

Material processing has become essential for the proper control, tuning and consequent application of the properties of micro/nanoparticles. In this case, we report herein the capability of the microwave-assisted hydrothermal (MAH) method to prepare the SrTiO3 compound, as a case study of inorganic compounds. Analyses conducted by X-ray diffraction, X-ray photoelectron and X-ray absorption spectroscopies confirmed that the MAH route enables the formation of pristine SrTiO3. The results indicated that the combination of thermal and non-thermal effects during the MAH treatment provides ideal conditions for an efficient and rapid synthesis of pristine SrTiO3 mesocrystals. Scanning electron microscopy images revealed a cube-like morphology (of ca. 1 μm) formed via a self-assembly process, influenced by the MAH time. Additionally, photoluminescence measurements revealed a broad blue emission related to intrinsic defects, which decreased with the MAH synthesis time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cp02893eDOI Listing
October 2019

Unusual Presentation of Ruptured Abdominal Aortic Aneurysm.

Rev Port Cir Cardiotorac Vasc 2019 Jan-Mar;26(1):71-73

Angiology and Vascular Surgery Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Abdominal aortic aneurysm affects 5-9% of the population over the age of 65 years; is more common in male smokers and in patients with a positive family history of aortic aneurysms. Most patients are asymptomatic; rupture is the most common and dreaded complication. The classical triad of back pain, hypotension and pulsatile mass is the most common presentation but is present in only 25-50% of patients. Clinical presentation seems dependent on rupture site. Our report illustrate a rare clinical presentation for a serious clinical condition. Knowledge of different presentations can lead to timely diagnosis and management and decrease in rupture related morbidity and mortality.
View Article and Find Full Text PDF

Download full-text PDF

Source
September 2019

[Aortic mural thrombus].

Rev Port Cir Cardiotorac Vasc 2019 Jan-Mar;26(1):19-26

Serviço de Angiologia e Cirurgia Vascular, Centro Hospitalar e Universitário de Coimbra, Portugal.

Aortic mural thrombus is a rare clinical finding in the absence of aneurysm or atherosclerosis but an important source of noncardiogenic emboli with a difficult diagnosis and a high rate of complications, including high mortality. It appears to occur more frequently in young adults usually with underlying pro-thrombotic disorder. With the increasing use of high resolution imaging, the asymptomatic mural thrombus became an increasingly frequent finding, but its potential for embolization or the best treatment are still a matter of debate. The management of mural thrombus in non-atherosclerotic aorta represents a challenge because no guidelines are available, and should be individualized. The therapeutic approach should include the triple aspects of aortic mural thrombus: primary disease anticoagulation treatment, surgical thrombectomy to solve embolic complications and endovascular/classical surgery to exclude the thrombus from the aorta. Historically therapeutic anticoagulation was proposed as first-line therapy and surgical intervention was reserved for mobile thrombus, recurrent embolism and contraindication for anticoagulation. However, it is associated with a 25-50% embolic recurrence rate, thrombus persistence in 35% and secondary aortic surgery in up to 31% of the cases. Recent data suggest that endovascular coverage of the aortic thrombus, when feasible, appears to be an effective and safe procedure with a low recurrence and re-embolization rates. In this article we review the published literature concerning this topic.
View Article and Find Full Text PDF

Download full-text PDF

Source
September 2019

Abdominal Aortic Aneurysm in Women: Retrospective Analysis of the Cases that Undergo Surgical Repair.

Rev Port Cir Cardiotorac Vasc 2017 Jul-Dec;24(3-4):150

CHUC, Portugal.

Introduction: The prevalence of infra-renal aortic abdominal aneurysms (AAA) is about 3 to 4 times higher in men, with a recommendation I 1a for screening men > 65y. Althoug women only represente 20% of the total AAAs they have a significant higher rupture rate - threefold higher - and a worse outcome after ruptured AAA repair. Screening is not consensual but can be recommended for women > 65y who have smoked or have a family history of AAA. Against screening is the fact that the AAA in women have not only a lower incidence but also a late presentation (>80y) but references have been made to the fact that smoking became popular more than 30 years after than men and so the effects just now can start to be seen.

Methods: A retrospective review was made to all women with an infra- renal AAA who undergo a surgical treatment, elective or urgent, in the past 7 years (January 2010 - August 2017) in our hospital. Information was obtained through the clinical process. It was made an evaluation of the demographic information and anatomic features.

Results: 15 cases were reviewed, 4 elective and 11 ruptured surgical repairs. The mean age was 74 and only 4 women were more than 80 years old, with a minium age of 57. More than half the patients were previously diagnosis with hypertension but only 30% had high cholesterol. Only one was a known smoker. None had a diagnosis of cardiac disease. One had a sintomatic cerebrovascular disease. Within the elective cases, all open repair, the intra-hospitalar mortality was zero with a mean stay of 7,5 days. The ruptured cases, 1 endovascular, had a perioperative mortality of 50% The mean aortic diametre at rupture was less than 6 cm.

Conclusion: Data supports the evidence of the morbidity of a ruptured AAA and the high intra-hospitalar mortality in women. Early detection and elective repair should be considered. Sex-specific research is needed to provide the best medical treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
May 2019

Endovascular Treatment of Femoral Anastomotic Aneurysm: Case Report and Review of Published Cases.

Ann Vasc Surg 2018 May 1;49:315.e15-315.e18. Epub 2018 Mar 1.

Serviço de Angiologia e Cirurgia Vascular, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, Coimbra, Portugal.

Anastomotic aneurysm is a possible complication after arterial reconstruction with highest incidence at femoral anastomosis; open surgery is the standard treatment, but endovascular exclusion can be useful in selected cases. The authors report a case of femoral anastomotic aneurysm, 19 years after aortobifemoral grafting, treated successfully using stent grafts, under local anesthesia and percutaneous brachial access. Review of published articles regarding endovascular management of femoral anastomotic aneurysm was performed. Endovascular exclusion of femoral anastomotic aneurysm is safe and feasible.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.avsg.2017.12.016DOI Listing
May 2018

Nature-Inspired Algorithm for Training Multilayer Perceptron Networks in e-health Environments for High-Risk Pregnancy Care.

J Med Syst 2018 Feb 1;42(3):51. Epub 2018 Feb 1.

ITMO University, Saint Petersburg, Russia.

Nature presents an infinite source of inspiration for computational models and paradigms, in particular for researchers associated with the area known as natural computing. The simultaneous optimization of the architectures and weights of artificial neural networks (ANNs) through biologically inspired algorithms is an interesting approach for obtaining efficient networks with relatively good generalization capabilities. This methodology constitutes a concordance between a low structural complexity model and low training error rates. Currently, complexity and high error rates are the leading issues faced in the development of clinical decision support systems (CDSSs) for pregnancy care. Hence, in this paper the use of a biologically inspired technique, known as particle swarm optimization (PSO), is proposed for reducing the computational cost of the ANN-based method referred to as the multilayer perceptron (MLP), without reducing its precision rate. The results show that the PSO algorithm is able to improve computational model performance, showing lower validation error rates than the conventional approach. This technique can select the best parameters and provide an efficient solution for training the MLP algorithm. The proposed nature-inspired algorithm and its parameter adjustment method improve the performance and precision of CDSSs. This technique can be applied in electronic health (e-health) systems as a useful tool for handling uncertainty in the decision-making process related to high-risk pregnancy. The proposed method outperformed, on average, other approaches by 26.4% in terms of precision and 14.9% in terms of the true positive ratio (TPR), and showed a reduction of 35.4% in the false positive ratio (FPR). Furthermore, this method was superior to the MLP algorithm in terms of precision and area under the receiver operating characteristic curve by 2.3 and 10.2%, respectively, when applied to the delivery outcome for pregnant women.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10916-017-0887-0DOI Listing
February 2018

Band alignment and charge transfer predictions of ZnO/ZnX (X = S, Se or Te) interfaces applied to solar cells: a PBE+U theoretical study.

Phys Chem Chem Phys 2018 Feb;20(7):4953-4961

Department of Physics, Federal University of Pelotas, P.O. Box 354, 96010-900, Pelotas, RS, Brazil.

The engineering of semiconductor materials for the development of solar cells is of great importance today. Two topics are considered to be of critical importance for the efficiency of Grätzel-type solar cells, the efficiency of charge separation and the efficiency of charge carrier transfer. Thus, one research focus is the combination of semiconductor materials with the aim of reducing charge recombination, which occurs by spatial charge separation. From an experimental point of view, the combining of materials can be achieved by decorating a core with a shell of another material resulting in a core-shell system, which allows control of the desired photoelectronic properties. In this context, a computational simulation is mandatory for the atomistic understanding of possible semiconductor combinations and for the prediction of their properties. Considering the construction of ZnO/ZnX (X = S, Se or Te) interfaces, we seek to investigate the electronic influence of the shell (ZnX) on the core (ZnO) and, consequently, find out which of the interfaces would present the appropriate properties for (Grätzel-type) solar cell applications. To perform this study, we have employed density functional theory (DFT) calculations, considering the Perdew-Burke-Ernzerhof (PBE) functional. However, it is well-known that plain DFT fails to describe strong electronic correlated materials where, in general, an underestimation of the band gap is obtained. Thus, to obtain the correct description of the electronic properties, a Hubbard correction was employed, i.e. PBE+U calculations. The PBE+U methodology provided the correct electronic structure properties for bulk ZnO in good agreement with experimental values (99.4%). The ZnO/ZnX interfaces were built and were composed of six ZnO layers and two ZnX layers, which represents the decoration process. The core-shell band gap was 2.2 eV for ZnO/ZnS, ∼1.71 eV for ZnO/ZnSe and ∼0.95 eV for ZnO/ZnTe, which also exhibited a type-II band alignment. Bader charge analysis showed an accumulation of charges in the 6th layer of ZnO for the three ZnO/ZnX interfaces. On the basis of these results, we have proposed that ZnO/ZnS and ZnO/ZnSe core-shell structures can be applied as good candidates (with better efficiency) for photovoltaic devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c7cp08177dDOI Listing
February 2018

Functionalized pink AlO:Mn pigments applied in prosthetic dentistry.

J Prosthet Dent 2017 Dec 3;118(6):771-777. Epub 2017 Apr 3.

Professor, Graduate Program in Materials Science and Engineering, Federal University of Pelotas, Pelotas, Brazil.

Statement Of Problem: The color of dental poly(methyl methacrylate) (PMMA) is conventionally rendered by organic and inorganic pigments, which are usually not bonded to the polymer network. Functionalized ceramic pigments can be used to color PMMA, allowing improved chemical interaction with the resin matrix.

Purpose: The purpose of this in vitro study was to synthesize, functionalize, and characterize pink manganese-doped alumina ceramic pigments. The hypothesis tested was that functionalized ceramic pigments would render pink coloration to a translucent PMMA without jeopardizing its mechanical properties.

Material And Methods: Pink alumina powders doped with 1 or 2 mol% of manganese (AlO:Mn) were prepared by means of a polymeric precursor method. Pigment (Pig.) particles were functionalized with a silica coating method followed by silanation before preparation of PMMA-based composite resins (5 wt% pigment). The color of composite resins (Pig.1% and Pig.2%) and PMMA controls (Pink and translucent [Trans]) was evaluated (CIELab color coordinates), and their mechanical properties were tested (3-point bending).

Results: The microstructure of the pigment particles showed approximately 55-nm nanocrystals of manganese-doped α-alumina clustered into irregular porous particles up to 60 μm. The composite resins and pink PMMA showed similar color parameters (CIE a* pink=20.1, Pig.1%=14.6, Pig.2%=16.0, Trans=0.19, P<.001; CIE b* Pink=17.0, Pig.1%=18.6, Pig.2%=19.0, Trans=2.52, P<.001). No statistical differences were observed in mechanical properties among groups (σ pink=98.4, Pig.1%=98.1, Pig.2%=98.8, trans=89.1, P=.136).

Conclusions: The addition of the functionalized pink ceramic pigments to a translucent PMMA yielded similar coloration to that of the regular pink PMMA used in dentistry and did not jeopardize its mechanical properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prosdent.2016.12.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5624818PMC
December 2017

Fingerprints of short-range and long-range structure in BaZr(1-x)HfxO3 solid solutions: an experimental and theoretical study.

Phys Chem Chem Phys 2015 May;17(17):11341-9

CCAF, Instituto de Física e Matemática (IFM), Departamento de Física, Universidade Federal de Pelotas, Campus do Capão do Leão, Caixa Postal, 354, CEP 96010-970, Pelotas, RS, Brazil.

A microwave-assisted hydrothermal method was applied to synthesize BaZr1-xHfxO3, (BZHO) solid solutions at a low temperature, 140 °C, and relatively short times, 160 min. The detailed features of the crystal structure, at both short and long ranges, as well as the crystal chemistry doping process, are extensively analysed. X-ray diffraction measurements and Raman spectroscopy have been used to confirm that pure and Hf-doped BZO materials present a cubic structure. Extended X-ray absorption fine structure (EXAFS) spectra indicate that Hf(4+) ions have replaced the Zr(4+) ions on the 6-fold coordination and a subsequent change on the Ba(2+) 12-fold coordination can be sensed. X-ray absorption near-edge structure (XANES) spectroscopy measurements reveal a local symmetry breaking process, associated to overlap of the 4d-2p and 5d-2p orbitals of Zr-O and Hf-O bonds, respectively. Field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM) show the mesocrystalline nature of self-assembled BZHO nanoparticles under a dodecahedron shape. In addition first principle calculations were performed to complement the experimental data. The analysis of the band structures and density of states of the undoped BZO and doped BZHO host lattice allow deep insight into the main electronic features. The theoretical results help us to find a correlation between simulated and experimental Raman modes and allow a more substantial interpretation of crystal structure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4cp05448bDOI Listing
May 2015

[Evaluation of the accessibility to the Specialized Dental Care Center within the scope of the macro region of Sobral, in the state of Ceará, Brazil].

Cien Saude Colet 2014 Jul;19(7):2235-44

Faculdade de Medicina de Sobral, Universidade Federal do Ceará, Sobral, CE, Brasil,

The Specialized Dental Care Center for the region of Sobral in the state of Ceará (CEO-R) has characteristics that render it unique, as it has regional coverage and is managed by a Local Health Consortium (which comprises 24 cities). It also works in conjunction with the School of Dentistry of the Federal University of Ceará - Sobral Campus, combining care and academic study in the same location. The scope of this article was to evaluate the accessibility to specialized care in this region with the implementation of this CEO-R. A descriptive-exploratory study with a quantitative approach was conducted by means of the collection and analysis of secondary data regarding the availability and usage of this service in addition to the application of semi-structured interviews with Oral Health Coordinators of the 24 municipalities in the consortium. The results showed that the CEO-R is equipped to meet the demand. However, geographic, financial and organizational barriers were detected, which explains the low rates of appointments scheduled and use of the services and the high rate of missed appointments, causing a significant financial impact on the cities included in the consortium.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1590/1413-81232014197.09862013DOI Listing
July 2014

Long-range and short-range structures of cube-like shape SrTiO3 powders: microwave-assisted hydrothermal synthesis and photocatalytic activity.

Phys Chem Chem Phys 2013 Aug 20;15(29):12386-93. Epub 2013 Jun 20.

Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, 13566-590, São Carlos, SP, Brazil.

We report herein a detailed study on the influence of microwave-assisted hydrothermal (MAH) treatment time on both long and short range structures around Ti atoms of SrTiO3 powders. Few studies have been carried out on short-order structural properties as well as the relationship between the local order and the SrTiO3 photocatalytic properties. We use X-ray diffraction to determine the long-range structure, while the local environment around the Ti atom is probed with X-ray absorption spectroscopy and the vibration frequencies are investigated by Raman spectroscopy. The faster crystallization of SrTiO3 powders provided by the MAH system resulted in large distortions of Ti-O bond lengths which remain unchanged even for a longer MAH treatment time. Despite the long-range structure being associated with ideal TiO6 clusters, X-ray absorption spectroscopy measurements identified the presence of undercoordinated TiO5 clusters. Compared with the reference bulk SrTiO3, the hierarchical SrTiO3 cube-like shape showed enhanced photocatalytic activity, which was associated with the presence of these TiO5 clusters. Field emission scanning electron microscopy (FE-SEM) revealed that the superstructures based on a cube-like shape are formed by an assembly process, becoming well defined as a function of MAH treatment time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c3cp50643fDOI Listing
August 2013

Joint experimental and theoretical analysis of order-disorder effects in cubic BaZrO3 assembled nanoparticles under decaoctahedral shape.

J Phys Chem A 2011 May 12;115(17):4482-90. Epub 2011 Apr 12.

Instituto de Química, LIEC, INCTMN, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.

Periodic first-principles calculations based on density functional theory at the B3LYP level has been carried out to investigate the photoluminescence (PL) emission of BaZrO(3) assembled nanoparticles at room temperature. The defect created in the nanocrystals and their resultant electronic features lead to a diversification of electronic recombination within the BaZrO(3) band gap. Its optical phenomena are discussed in the light of photoluminescence emission at the green-yellow region around 570 nm. The theoretical model for displaced atoms and/or angular changes leads to the breaking of the local symmetry, which is based on the refined structure provided by Rietveld methodology. For each situation a band structure, charge mapping, and density of states were built and analyzed. X-ray diffraction (XRD) patterns, UV-vis measurements, and field emission scanning electron microscopy (FE-SEM) images are essential for a full evaluation of the crystal structure and morphology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jp1119124DOI Listing
May 2011

Enamel-resin bond durability of self-etch and etch & rinse adhesives.

Am J Dent 2009 Dec;22(6):371-5

Department of Dental Materials, Dental School, University of Granada, Colegio Máximo, Campus de Cartuja s/n 18017 Granada, Spain.

Purpose: To evaluate the degradation of resin-enamel interfaces bonded with different adhesive systems.

Methods: Flat enamel surfaces were ground buccally on bovine incisors. Two etch & rinse self-priming adhesives (Single Bond, Prime & Bond NT), three two-step self-etch adhesives (Clearfil SE Bond, Resulcin Aquaprime, NRC/Prime & Bond NT) and two all-in-one adhesives (Etch & Prime 3.0, Adper Prompt-L-Pop) were used for bonding. A hybrid resin composite (Tetric Ceram) was selected for coronal build-up. Bonded specimens were stored in water at 37 degrees C for 24 hours, 6 months and 1 year, respectively, and then sectioned into 1 mm2 beams. Each microtensile stick was loaded in tension until failure (crosshead speed: 0.5 mm/minute). Bond strength data were analyzed with two-way ANOVA and Student Newman Keuls tests (P < 0.05). Etching patterns resulting from phosphoric acid etching and self-etch adhesives application on ground enamel were analyzed under SEM.

Results: All adhesives attained similar bond strengths after 24 hours. All-in-one adhesives and Resulcin Aqua Prime recorded a significant reduction in bond strengths after 6 months and 1 year of water aging.
View Article and Find Full Text PDF

Download full-text PDF

Source
December 2009

Advanced stage of oral myiasis in children: a clinical case report.

Quintessence Int 2008 Jan;39(1):39-43

Federal University of Pará, Belém, Pará, Brazil.

Human myiasis is characterized by larval infestation of body tissues or cavities of live individuals. Although most frequently observed in underdeveloped and tropical countries, reports of human myiasis have been encountered throughout the world. Conventional treatment is the mechanical removal of the larvae, one by one, which is painful and embarrassing and repugnant to both health professional and patient. Even though human myiasis is not considered rare, most dental professionals have very little knowledge of the diagnosis and treatment of this pathology. The purpose of this article, therefore, is to report a case of advanced-stage oral myiasis in a 9-year-old patient treated at a health and dentistry clinic. Diagnosis was based on visual observation of Cochliomyia hominivorax larvae, a dipterous fly of the Calliphoridae family, which were between the second and third stages of development. Predisposition factors include lack of information, malnutrition, poor oral hygiene, preexistence of oral lesions, and severe halitosis, which decisively influence the appearance and development of oral myiasis. A brief review of the literature is also included, in which the importance of early clinical diagnosis, myiasis etiology, and possible associations with other pathologies and different types of treatment are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
January 2008

[Cotard's delusion of negations].

Acta Med Port 2004 Jan-Feb;17(1):106-8. Epub 2004 Feb 27.

Hospital de Magalhães Lemos, Porto.

The authors report a clinical case of a sixty-two-year-old woman admitted to hospital because Cotard's nihilistic delusion in a one year major depressive episode. The patient was treated with clomipramine and olanzapine with a rapid improvement and normalisation of humor and delusions.
View Article and Find Full Text PDF

Download full-text PDF

Source
January 2006

Effect of the hydration status of the smear layer on the wettability and bond strength of a self-etching primer to dentin.

Am J Dent 2004 Oct;17(5):310-4

Department of Dental Materials, School of Sciences, University of Granada, Spain.

Purpose: To evaluate the microtensile bond strength (MTBS) of a resin-based composite to smear layer-covered dentin using a self-etching primer, Clearfil SE Bond (CSEB), under two different hydration states. Surface roughness and wettability (contact angle measurements) of water and the CSEB primer were also evaluated on this substrate.

Methods: Contact angle (CA) measurements were performed on four caries-free extracted human third molars. The specimens were sectioned parallel to the occlusal surface to expose the moderately deep dentin and ground flat (180-grit SiC) under water to provide uniform flat surfaces. In two samples, the smear layer was completely air-dried; in the other two specimens, the smear layer was briefly air-dried. Contact angle measurements were performed to assess wettability of water and CSEB primer using the Axisymmetric Drop Shape Analysis technique. Surface roughness (SR) was determined with a contact profilometer. In another four molars, CSEB was applied to the smear layer-covered dentin with both hydration states. Resin build-ups were performed incrementally with Tetric Ceram. After storage for 24 hours in water at 37 degrees C, the teeth were sectioned to obtain bonded beams with an average cross-sectional area of 1.0 mm2. Each beam was tested in tension in an Instron machine at 0.5 mm/minute. Kolmogorov-Smirnov and Student t-tests were performed at a 95% significance level.

Results: Observed water contact angles were lower on the hydrated smear layer but no differences were found between contact angles on completely and briefly air-dried smear layer when the primer was used for CA measurements. SR was similar for both substrates and MTBS was greater when the adhesive was applied on the completely air-dried smear layer.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2004